Correct Answer - Option 1 : RTU
Explanation:
Remote Terminal Units (RTUs):
- These gathers the information from various field sites in which they are employed.
- Each RTU is connected with various sensors and actuators that manage the local processes or field equipment.
- It collects the information from various sensors and sends the information to the MTU.
- Also, it receives the control commands from MTU and correspondingly controls the various actuators.
- Many RTUs store the data in their database and waits for a request from the MTU to send or transmit the data.
- In sophisticated systems, PLCs are used as RTUs which directly transfer the field data and controls the parameters without a request from the MTU.
- It uses a local area network to communicate with various field intelligent devices.
Master Terminal Unit (MTU):
- It is the heart of the SCADA system, which can be a dedicated computer, a Programmable Logic Controller (PLC), or a network server that communicates with remote field-side RTUs.
- It initiates all communication, collects the data, stores the data in the database, provides interfaces to operators, and sends the information to other systems.
- It allows the users to perform controlling functions on field devices such as breakers, switches, and other actuators depending on the gathered data.
- It continuously communicates with other devices in the master station so as to facilitate data logging, alarm processing, trending and reporting, graphical interface, and security system.
